Hydraulic metal tube press



Sept 23, 1969 HANs-HENNING cRosEcK ETAL 3,468,152

HYDRAULIC METAL TUBE PRESS Filed May 3, 1966 Illll.

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HAms-HENNING CRosEm AUGUST GROHMHNN 3T /W/uf M ffm/V United StatesPatent O im. c1. imc zszo; B215 9/18 U.S. Cl. 72-265 5 Claims ABSTRACT FTHE DISCLOSURE A hydraulic metal tube extrusion press comprises astationary press cylinder having a driving piston which is slidabletherein. A mandrel is slidable in the driving piston and includes theusual stroke limiting stop means permitting it to be moved between twoextreme positions. The mandrel includes a rear portion extending outthrough the driving piston and the press cylinder. In order to absorbthe reaction force or back pressure which is formed in the press whenthe mandrel has pierced the workpiece in a pressing position the mandrelis braced to the main cylinder by a lock. In the embodiment shown, thelock comprises a power operated latch or coupling member which moves invertical guides and engages around abutting flanges of the mandrel.

This invention relates, in general, to the construction of hydraulicpresses and, in particular, to a new and useful metal tube press havingan internal means for bracing the main mandrel.

The present invention particularly deals with a hydraulic extrusionpress of the type having a main press piston which is slidable in acylinder and which includes a press mandrel rod which is directed outthrough the rear end of the cylinder without requiring that the mainpiston have a rear extension or that there be a front distance piecebetween the press piston and the barrel spar or an extended portion ofthe barrel spar. A problem with presses of this nature has heretoforebeen one of absorbing the reaction forces. If this is not done, then thetotal pressing force for which the press is designed is not availablefor pressing out but is partially consumed.

Reaction forces become operative in the press, for example, whenpressing out is done with a recessed or stopped mandrel. The reactionforce is the force component of the pressing material enclosed betweenthe press disk, container wall, and matrix which acts in particular onthe mandrel shoulder and counter to the pressing direction of themovable part or the broaching device. This pressing force may be 40% andmore of the total pressing force and must consequently be substractedfrom the total pressing force when determining the actual pressingforce.

The problem underlying the invention, that is, of absorbing the reactionforce is solved according to the invention by providing a moving part ofthe broaching device, in particular, the mandrel rod which is rigidlyconnected with the mandrel driving piston, with a bracing. The bracingin the desired position of the mandrel is preferably on theself-enclosed force absorbing system of the press which consistsessentially of a main drive press bar, the counter spar and the tractionelements connecting them. In accordance with the invention, the mandrelmay be braced on any desired stationary part of the press or a basewhich is secured to the ground. By bracing the mandrel in this manner,it is possible to make use of the total pressing force for which thepress is designed.

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According to another characteristic of the invention, the mandrel rod isconnected with every movable part of the press which is able to absorb areaction force by means of a power operated lock or coupling. For thispurpose, the mandrel rod must be provided with an abutment or stop suchas a coupling flange or a groove which can be connected either by twopower operated latches or coupling claws with a stationary stop orcoupling ange of the press. In a preferred arrangement, the latchingmechanism includes coupling members which are movable crosswise to theaxis of the mandrel rod and are positively guided preferably in thedirection of movement and normal thereto.

Accordingly, it is an object of the invention to provide an improvedhydraulic press which includes a mandrel rod which is extended throughits associated cylinder and with means for bracing the rod at theportion thereof which extends through the cylinder for accomplishing apressing operation.

A further object of the'invention is to provide a hydraulic press whichincludes a mandrel piston in which is slidable a mandrel rod whichcontinues through the cylinder therefor rearwardly and is provided witha latching member which may be latched to a fixed end of the cylindersuch as by a movable latching mechanism.

A further object of the invention is to provide a hydraulic press whichis simple in design, rugged in construction and economical tomanufacture.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which there is illustrated and described a preferredembodiment of the invention.

In the drawings:

FIG. 1 is a longitudinal sectional View of an extrusion pressconstructed in accordance with the invention;

FIG. 2 is a view similar to FIG. l with the parts in differentpositions; and

FIG. 3 is an enlarged partial elevational and sectional view of amandrel tip.

Referring to the drawings, in particular, the invention embodied thereinincludes a main driving cylinder 1 in which there is guided a main presspiston or plunger 2. The front end of the piston 2 is provided with abarrel spar 3 which is secured thereto and guided on a bed 4. A ram 5 isdisposed in the barrel spar 3 and it is indicated in position engaged ina pressing disk 6 of a pressing block 7 arranged within a container 8.

The rear portion of the pressing piston 2 is provided with an openingthrough which a driving piston portion 10 of the mandrel 11 is located.The piston 10 is axially slidable and rotatable within the associatedcylinder 9. Between the mandrel 11 and the driving piston 10 there isprovided a multipart connecting rod system 12.

ln accordance with the invention, the back of the mandrel 11 extendsthrough the driving cylinder 9 and is provided with a rod portion 13which extends outwardly through the rear of the cylinder 1. The outerend is provided with a thread 14 and a fastening nut 16 is threadedthereover against a movable stop 15. On the side of the stop 15 facingthe press, there is provided a coupling flange 18. An extension 17 whichis rigidly connected to the main press cylinder 1 includes a couplingflange 19 and it comprises part of the self-enclosed forces absorbingsystem of the press.

In the desired position of the mandrel 11 for the pressing out of thepress piston 7, the stop 15 can be brought to apply with its iiange 18against the ange 19 of the extension 17. By securing the nut 16, thestop 15 is held in a iixed position.

When pressing out, for example, by means of a -recessed mandrel 11, asshown in FIG. 3i, the mandrel tip 11 is arranged inside the press matrix23. (This is the desired position). The transition from the mandrel tip11 to the mandrel shank 11 is designated 11". The distance between themandrel transition 11" and the end face of the matrix 23 is designatedby the small letter p and the difference between the diameters 11 and 11by the letter f. The reaction force is P =p f. This force acts in thedirection of the arrow of FIG. 3.

In order to absorb the reaction force Pr, according to the inventiveidea, the mandrel rod 13 is braced to the main cylinder 1 by a lockafter the workpiece has been pierced so that the workpiece may beextended Without further advancing travel of the mandrel. To lock themandrel rod 13 with the stationary main press cylinder 1, there isprovided a power operated latch or coupling member 21 which slides invertical guides 20 in the direction of the mandrel rod 13. The couplingmember 21 includes claw projections 22 which engage around the abuttingflanges 18 and 19 in such a manner that the mandrel rod is retained oris held fast and is therefore fully braced to the stationary cylinder 1.

While a specic embodiment of the invention has been shown and describedin detail to illustrate the application of the inventive principles, it4will be understood that the invention may be embodied otherwise Withoutdeparting from such principles.

What is claimed is:

1. A hydraulic metal tufbe extrusion press comprising a stationary presscylinder, a driving piston slidable in said press cylinder, said presscylinder and said piston deiining a fluid pressure chamber which isadapted to be pressurized to mave said drive piston relative to saidpress cylinder, a mandrel having stroke limiting stop means and beingslidable in said driving piston between two extreme positions and havinga rear portion extending out through said driving piston and said presscylinder, a second cylinder and piston means for actuating said mandrel,and bracing means on said press cylinder engageable with said mandrel ina pressing position after the workpiece has been pierced for anchoringsaid mandrel to said press cylinder to brace the rear portion of saidmandrel.

2. A hydraulic metal tube press, according to claim 1, wherein saidmandrel stroke limiting stop means is at the rear thereof, means foradjustably positioning said stop member 0n said mandrel, and a lockingmember movable to engage said stop member and to hold said stop memberin a fixed position.

3. A hydraulic metal tube press, according to claim 2, including anextension formed on said press cylinder, said stop means adapted to abutagainst said extension, said bracing means locking said stop member withsaid mandrel in respect to said extension.

4. A hydraulic metal tube press comprising a stationary press cylinder,a driving piston slidable in said press cylinder, a mandrel slidable insaid driving piston between two extreme postions and having a rearportion extending out through said driving piston and said presscylinder, means for bracing the rear portion of said mandrel in apressing position, said mandrel including a stop memlber at the rearthereof, means for adjustably positioning said stop member on saidmandrel, a locking member movable to engage said stop member and to holdsaid stop member in a fixed position, an extension formed on said presscylinder, said stop member adapted to abut against said extension, meansfor locking said stop member with said mandrel in respect to saidextension, said stop member and said extension have abutting anges, saidlocking means including a member engageable around said anges to holdsaid stop member and said extension against relative movement.

5. A hydraulic metal tube press, according to claim 4, wherein said stopmember is slidable on said mandrel, and a nut for locating said stopmember which is threaded onto said mandrel.

References Cited UNITED STATES PATENTS 861,194 7/1907 schwieger 'l2-265878,092 2/1908 Schwieger 72-265 3,190,102 6/1965 Mener 72-265 CHARLES W.LANHAM, Primary Examiner GENE P. CROSBY, Assistant Examiner U.S. C1.X.R. 72-453 l

